Photographic shutter



Juhell, 1929. w. IAUERSFELD ET AL 1.716.512

PHOTOGRAPHI'C SHUTTER Filed larch 30, 1928 e7 n 2 t:::::;::::: I 2 i v aI \M u pluL L Fig. 4 b Jwentons:

' The shutter shown contains 45 worm i,

- Patented June 11', 1929.

wALTmm BAUEBSFELD AND FRANKLIN PFEIFFEB, or TO THE FIRM CARL ZEISS, orJENA,

JENA, GERMANY, ASSIGNORS GERMANY.

V PHOTOGRAPHIC SHUTTER.

Application ma March-30, 1928, Serial No.

' The present invention relates to photographic shutters, which are tobe disposed at the locus of't'he camera objective and wlnch contaih aplurality of rotatable shutter 5 blades, partly overlapping each other.The invention corisists in this that with these shutters :the bladesare. constructed as spherical bowls,and not, as heretofore, as planediscs. Thereby-one attains in the first lacea great rigidity of theblades, so as to able to render them particularly thin; moreover, a verycompact structure of the shutter is thereby attained.

The annexed drawing shows as an example a shutter according to theinvention.

Fig. 1 represents a section through the shutter along the objectiveaxis. Fig.- 2 a perspective view of the shutter with the casing removed,looking in the direction of the arrow shown in Fig. 1, Fig. 3 a frontview of one of the shutter blades and Fig. 4 a section on theline 4-4 ofFig. 1.

four blades a, recessed according to Fig. 3 and constructed as sphericalbowls, which are rotatably supported on'a spherical casing b with axesc. On the latter are fixed driving wheels (1, engaging in a gears of'a'bevel wheel erotatable about the casing b. The bevel wheel has also asecond gear a, coacting with a curved wheel f, which is rotatablysupported on the casing by means of an axis g. On the wheel f there arefixed two ratchet wheels f and f. By means of two ratchets h and bengagin these wheels, the latter and also the eel f are coupled to aspring casing 2' on which the ratchets are fixed rotatable about an axish, The spring casing is likewise rotatable about the axis 9 andwithin'the same 40 there is so ported a spirial spring 2'. The

one end o this spring is fastened in the spring casing z', whilst theother is rigidly connected to a worm wheel 1', rotatable about the axisg. The worm wheel meshes with a which is supported .on a standard fixedon the base I) of the casing and provided with a milled head i. Thespring casing carries in addition a handle 2', two noses i and iand astop 2', which during clock- 7 wise rotations'of the spring casingstrikes against a plate 7', fixed on the standardj. Between the wormwheel 2' and the spring casing i there is disposed a spur wheel k, whichis rigidly connected to the worm wheel provided a spherical body 12-, toreceive a part of the 266,072, and in Germany February 8, 1926.

2' and engages in a wheel 70 The latter is supported on a standard [afixed on the base plate 6 and engages in a toothed sector Z, which isrotatable about a bolt Z fixed on the spherical part of the casing b. Onthe bolt is fixed a spring casing Z in which is disposed a spiral springZ the one end of which is fixed on the nave of the toothed sector I. Theother end of the spring is free and extends below the nose 2" of thespring casing 2'. To the casing b of the shutter there is also rigidlyconnected a pin m which serves for releasing the ratchet 1L Besidesthere is which is destined photographic objective, whilst the other partof the objective'is to be fixed on the casing itself. In addition, thereis provided a disengaging friction brake for the wheel f whose frictiondisc is formed by the wheel i. As a brake shoe serves the head 0 of arod 0, which is guided in a sleeve 0 fixed on the base plate I), andwhich rod is under the action of a spring 0 The sleeve 0 has a slot 0.through which passes a pin 0", fixed on the rod 0 The pin 0 extendsbehind a pawl 12 to be released by hand and being under the action ofaspring p, which is supported on the base plate I) at a standard p Allactuating parts of the shutter are covered by a lid N.

The operation of the shutter takes place in the following we The shutteris to be wound up by rotating clockwise the spring casing Thereby thelatter is rotated by means of the handle i until the stop i strikesagainst the plate 7' in which case the pawl facts behind the nose 2'",so as to prevent the spring casing from turning back. On rotating thespring casing the ratchet k slips along the pin m, viz, in the firstplace with a part concentric with the axis of rotation g of the springcasing, so that the position of the ratchet it does not undergo achange. Consequently, the ratchet remains in mesh with the ratchet Wheel7, and the latter with the wheel 7 as well as the bevel wheel e, thedriving wheels d and the blades a are turned backwards together with thespring casing. The arrangement is such that the blades a are thusrotated in a backward direction through 60. After the rotation of thespring casing 2', corresponding to the aforesaid angle, the ratchet Itcomes to lie under the pin m with a part projecting beyond that part ofit which is concentric with its axis of roleases the wheel 7. At thesame time there is released the nose 2' and the spring casing i jerksback into its original position. Thereby the ratchet if rotates theratchet wheel f and the blades a; these latter are rotated through 420.so that they resume that position which they held prior to thewinding-upot'thc shutter. During the rotation of the blades a through420 all. recesses of the blades come to lie simultaneously in front ofthe lenses ot-the objective. whereby the shutter is at full aperture.However, the opening does not begin simultaneously with the jerking backof the spring casing but only after the latter and all parts to be movedhave been moved somewhat. Thereby it is attained that during the properopening-period the blades (0 move at a uniform speed and need not firstbe accelerated during this period. At the end of the opening period thenose '5 strikes against the free end of thespiral spring Z" by which-ashock atthe end of the motion of the blades is prevented. In order thatsufiic-ient ranges for the initial acceleration for the opening-periodand for the gradual standstill ot the masses are available, one. haschosen the comlniratively large angle of rotation of the blades of l-lflwhich necessitates a backward movement of the blades by the amountsurpassing 360 at the beginning of the winding-up of the shutter.

The variation of theelasticity of the act-uating spring 71 and of theduration of the opening-period is eflI'ected by rotating the milled headi Thereby one also-attains a variation of the elasticity of the spring Zso that to the amount of the force actuating the blades a, there alwayscorresponds the amount of the force lessening the motion of the bladesat the finish.

e claim:

1. Photographic shutter, comprising a plurality of shutter bladesrotatably disposed, these blades having the shape of spherical bowls aspring for actuating the shutter blades, means for winding up thisspring, coupling means adapted to impart tothe shutter blades, on thesaid spring'being wound up,

a rotation through over 360, and means for releasing the spring.

2. Photographic shutter, comprising a plurality of shutter bladesrotatably disposed, these blades having the shape of spherical bowls, aspring for actuating theshutter blades, and a second spring for checkingthe motion of the shutter blades. v

3. Photographic shutter, comprising a plurality ot' shutter bladesrotatably disposed, these blades having the shape of spherical bo\\'ls,'a spring for actuating the shutter blades, :1 second spring for checkingthe mo-.

tion of the shutter blades, and means for simultaneously varying theelastlcity 0t both springs in the same sense.

WALTHER BAUERSFELD. FRANKLIN PFEIFFER.

